In recent years there have been introduced many automobile anti-theft alarm systems for deterring theft of automobiles. Such anti-theft alarm systems include a sensing mechanism for detecting an intrusion. The sensing mechanism is connected to a control circuit for indicating an alarm condition signal in response to an intrusion. The alarm condition signal then energizes an audible alarm, siren, or other sound emitting device. These automobile anti-theft alarm systems are typically activated by the driver after the driver has parked the automobile, locked it, and left. There are also passive alarm systems which arm themselves after some predetermined time period after the vehicle is turned off and all doors are closed. The automobile anti-theft alarm system typically includes a vehicle pin switch or shock sensor to detect a door opening, or motion sensor or glass breaking sound detector which detects any unauthorized motion or harm to the parked vehicle, such as would occur when an intruder is attempting to enter the vehicle, such as by breaking the window or picking a lock, or when the user gets into the vehicle. This intrusion sensor sends a signal to emit an alarm. Typical anti-theft alarm systems can be connected to the existing automobile horn of the vehicle, or can have their own separate siren installed which may be powered either by the battery of the automobile or an additional internal battery. The sound emitting device is typically mounted under the locked hood or trunk of the vehicle. In addition, the alarm control circuit is typically installed also within a secured area of the vehicle, such as under the dash board of the car.
To arm and disarm the anti-theft alarm system, it is important that the user be physically removed from the vehicle so that the user does not set off an alarm condition when arming or activating the system. Accordingly, some systems use a hand-held remote control unit which communicates with the alarm control circuit installed in the vehicle to activate and arm the system to detect intrusions. Also, passive alarm systems arm themselves as mentioned above. These remote control units arm and disarm the anti-theft system by transmitting a signal to the system installed in the automobile. To notify and acknowledge to the user that the system has indeed been armed or disarmed, virtually all remote and passive alarming systems include a notification feature whereby receipt of the remote control signal causes the alarm sound emitting device to generate a short, loud burst of sound, sometimes referred to as a chirp. Typically, such chirps are essentially of a short, predetermined duration of about one to one and one-half seconds of energizing of the sound emitting device of the anti-theft system, typically at the same intensity or volume as an alarm condition. Consequently, this loud chirp, although of relatively short duration, can become very annoying to others who may be within the vicinity of the automobile.
While this nuisance is something which can perhaps be tolerated during the daylight hours, it can become extremely troublesome when the anti-theft system is armed or disarmed at night. This is especially true when people return home in the evening and park their car at their house or apartment parking lot, and arm the anti-theft system in their car for the night. Depending on the time of the evening, many people within hearing range may be awakened by the arm chirp. This is especially true in apartment complexes when there are many cars parked outside the windows of people who may be trying to sleep at night. It is also an annoyance which can be heard through the walls of a typical house, which may include a garage which may have other people or children in the house sleeping. It may also awaken people in the morning when the anti-theft system is disarmed to allow the driver to use the vehicle. On the other hand, to fail to arm the vehicle is not acceptable since many automobile and automobile accessory thefts occur at night. Also, some systems allow manual disabling of the arm/disarm chirp, but it disables it at all times, day or night.
In light of the foregoing, it is therefore an object of the present invention to provide an apparatus which automatically suppresses the audible arm and disarm chirps of a remote control automobile anti-theft system. It is another object of the present invention to provide an apparatus for automatically suppressing the arm and disarm chirp during the evening. It is yet another object of the present invention to provide an apparatus for suppressing an audible arm and disarm chirp which apparatus is durable and reliable in its operation. It is still another object of the present invention to provide an apparatus for suppressing an audible arm and disarm chirp which is cost-effective in its manufacture and simple and convenient to use.